Influence of different stabilizing operations and storage time on the composition of essential oil of thyme (Thymus officinalis L.) and rosemary (Rosmarinus officinalis L.)

Abstract The effect of different stabilizing techniques on the composition of essential oil of rosemary (Rosmarinus officinalis L.) and thyme (Thymus officinalis L.) during one year of storage is reported. The study was aimed to know what is the stabilizing technique to keep at the best the original essential oil composition. The fresh samples were collected and treated as follows: air-dried in a laboratory scale pilot dryer, frozen in a forced-air freezer and freeze-dried in a laboratory freeze-dryer. The fresh sample served as control. The treated samples were packaged with appropriate packaging material and stored at 20 °C or −20 °C for 12 months. All the samples were hydrodistilled every three months and the oils composition was obtained by means of gas chromatography/mass spectrometry (GC/MS). Quantification of known compounds was done with the use of an internal standard. Freezing best maintained the composition of rosemary and thyme essential oil. Appropriate packaging of air-dried and freeze-dried herbs resulted in negligible quality loss up to one year of storage. The frozen and stored thyme samples showed the best retention of thymol, the most important compound, as well as of γ-terpinene and carvacrol

Influence of storage time on the composition of volatile compounds of air dried, frozen and freeze dried thyme and rosemary cultivated in Sardinia

This paper deals with the effect of different stabilizing techniques on the evolution of the volatiles in rosemary (Rosmarinus officinalis L.) and thyme (Thymus officinalis L.) cultivated in Sardinia during nine months of storage. Fresh leaves were collected and soon divided in four batches, which were subjected to hydro distillation and GC-MS analysis, the first batch as fresh, the second one after drying in a laboratory pilot dryer, the third after freezing in a forced air freezer and the fourth after freeze drying in a laboratory freeze dryer. AlI the samples were adequately packaged and stored. Samples for analysis were taken at 3 months intervals. The fresh, stabilised and stored plant material were hydro distilled for 4 hours using a Clevenger-type. The oils were analysed in duplicate by gas chromatography, using a flame ionization detector. Qualitative analysis was done by GC /Mass and mass units were monitored from 10 to 450 at 70 eV. Results of the evolution of volatile compounds of the differently samples seem to evidence that the best way to stabilize the herbs is freezing

Neutralization Interfering Antibodies: A “Novel” Example of Humoral Immune Dysfunction Facilitating Viral Escape?

The immune response against some viral pathogens, in particular those causing chronic infections, is often ineffective notwithstanding a robust humoral neutralizing response. Several evasion mechanisms capable of subverting the activity of neutralizing antibodies (nAbs) have been described. Among them, the elicitation of non-neutralizing and interfering Abs has been hypothesized. Recently, this evasion mechanism has acquired an increasing interest given its possible impact on novel nAb-based antiviral therapeutic and prophylactic approaches. In this review, we illustrate the mechanisms of Ab-mediated interference and the viral pathogens described in literature as able to adopt this “novel” evasion strategy